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ff7d6b27 JDB |
1 | /* SPDX-License-Identifier: GPL-2.0 |
2 | * | |
3 | * page_pool.h | |
4 | * Author: Jesper Dangaard Brouer <netoptimizer@brouer.com> | |
5 | * Copyright (C) 2016 Red Hat, Inc. | |
6 | */ | |
7 | ||
8 | /** | |
9 | * DOC: page_pool allocator | |
10 | * | |
11 | * This page_pool allocator is optimized for the XDP mode that | |
12 | * uses one-frame-per-page, but have fallbacks that act like the | |
13 | * regular page allocator APIs. | |
14 | * | |
15 | * Basic use involve replacing alloc_pages() calls with the | |
16 | * page_pool_alloc_pages() call. Drivers should likely use | |
17 | * page_pool_dev_alloc_pages() replacing dev_alloc_pages(). | |
18 | * | |
99c07c43 JDB |
19 | * API keeps track of in-flight pages, in-order to let API user know |
20 | * when it is safe to dealloactor page_pool object. Thus, API users | |
21 | * must make sure to call page_pool_release_page() when a page is | |
22 | * "leaving" the page_pool. Or call page_pool_put_page() where | |
23 | * appropiate. For maintaining correct accounting. | |
ff7d6b27 | 24 | * |
99c07c43 JDB |
25 | * API user must only call page_pool_put_page() once on a page, as it |
26 | * will either recycle the page, or in case of elevated refcnt, it | |
27 | * will release the DMA mapping and in-flight state accounting. We | |
28 | * hope to lift this requirement in the future. | |
ff7d6b27 JDB |
29 | */ |
30 | #ifndef _NET_PAGE_POOL_H | |
31 | #define _NET_PAGE_POOL_H | |
32 | ||
33 | #include <linux/mm.h> /* Needed by ptr_ring */ | |
34 | #include <linux/ptr_ring.h> | |
35 | #include <linux/dma-direction.h> | |
36 | ||
e68bc756 LB |
37 | #define PP_FLAG_DMA_MAP BIT(0) /* Should page_pool do the DMA |
38 | * map/unmap | |
39 | */ | |
40 | #define PP_FLAG_DMA_SYNC_DEV BIT(1) /* If set all pages that the driver gets | |
41 | * from page_pool will be | |
42 | * DMA-synced-for-device according to | |
43 | * the length provided by the device | |
44 | * driver. | |
45 | * Please note DMA-sync-for-CPU is still | |
46 | * device driver responsibility | |
47 | */ | |
48 | #define PP_FLAG_ALL (PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV) | |
ff7d6b27 JDB |
49 | |
50 | /* | |
51 | * Fast allocation side cache array/stack | |
52 | * | |
53 | * The cache size and refill watermark is related to the network | |
54 | * use-case. The NAPI budget is 64 packets. After a NAPI poll the RX | |
55 | * ring is usually refilled and the max consumed elements will be 64, | |
56 | * thus a natural max size of objects needed in the cache. | |
57 | * | |
58 | * Keeping room for more objects, is due to XDP_DROP use-case. As | |
59 | * XDP_DROP allows the opportunity to recycle objects directly into | |
60 | * this array, as it shares the same softirq/NAPI protection. If | |
61 | * cache is already full (or partly full) then the XDP_DROP recycles | |
62 | * would have to take a slower code path. | |
63 | */ | |
64 | #define PP_ALLOC_CACHE_SIZE 128 | |
65 | #define PP_ALLOC_CACHE_REFILL 64 | |
66 | struct pp_alloc_cache { | |
67 | u32 count; | |
68 | void *cache[PP_ALLOC_CACHE_SIZE]; | |
69 | }; | |
70 | ||
71 | struct page_pool_params { | |
72 | unsigned int flags; | |
73 | unsigned int order; | |
74 | unsigned int pool_size; | |
75 | int nid; /* Numa node id to allocate from pages from */ | |
76 | struct device *dev; /* device, for DMA pre-mapping purposes */ | |
77 | enum dma_data_direction dma_dir; /* DMA mapping direction */ | |
e68bc756 LB |
78 | unsigned int max_len; /* max DMA sync memory size */ |
79 | unsigned int offset; /* DMA addr offset */ | |
ff7d6b27 JDB |
80 | }; |
81 | ||
82 | struct page_pool { | |
ff7d6b27 JDB |
83 | struct page_pool_params p; |
84 | ||
c3f812ce JL |
85 | struct delayed_work release_dw; |
86 | void (*disconnect)(void *); | |
87 | unsigned long defer_start; | |
88 | unsigned long defer_warn; | |
89 | ||
90 | u32 pages_state_hold_cnt; | |
99c07c43 | 91 | |
ff7d6b27 JDB |
92 | /* |
93 | * Data structure for allocation side | |
94 | * | |
95 | * Drivers allocation side usually already perform some kind | |
96 | * of resource protection. Piggyback on this protection, and | |
97 | * require driver to protect allocation side. | |
98 | * | |
99 | * For NIC drivers this means, allocate a page_pool per | |
100 | * RX-queue. As the RX-queue is already protected by | |
101 | * Softirq/BH scheduling and napi_schedule. NAPI schedule | |
102 | * guarantee that a single napi_struct will only be scheduled | |
103 | * on a single CPU (see napi_schedule). | |
104 | */ | |
105 | struct pp_alloc_cache alloc ____cacheline_aligned_in_smp; | |
106 | ||
107 | /* Data structure for storing recycled pages. | |
108 | * | |
109 | * Returning/freeing pages is more complicated synchronization | |
110 | * wise, because free's can happen on remote CPUs, with no | |
111 | * association with allocation resource. | |
112 | * | |
113 | * Use ptr_ring, as it separates consumer and producer | |
114 | * effeciently, it a way that doesn't bounce cache-lines. | |
115 | * | |
116 | * TODO: Implement bulk return pages into this structure. | |
117 | */ | |
118 | struct ptr_ring ring; | |
99c07c43 JDB |
119 | |
120 | atomic_t pages_state_release_cnt; | |
1da4bbef IK |
121 | |
122 | /* A page_pool is strictly tied to a single RX-queue being | |
123 | * protected by NAPI, due to above pp_alloc_cache. This | |
124 | * refcnt serves purpose is to simplify drivers error handling. | |
125 | */ | |
126 | refcount_t user_cnt; | |
7c9e6942 JDB |
127 | |
128 | u64 destroy_cnt; | |
ff7d6b27 JDB |
129 | }; |
130 | ||
131 | struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp); | |
132 | ||
133 | static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool) | |
134 | { | |
135 | gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN); | |
136 | ||
137 | return page_pool_alloc_pages(pool, gfp); | |
138 | } | |
139 | ||
bb005f2a IA |
140 | /* get the stored dma direction. A driver might decide to treat this locally and |
141 | * avoid the extra cache line from page_pool to determine the direction | |
142 | */ | |
143 | static | |
144 | inline enum dma_data_direction page_pool_get_dma_dir(struct page_pool *pool) | |
145 | { | |
146 | return pool->p.dma_dir; | |
147 | } | |
148 | ||
ff7d6b27 JDB |
149 | struct page_pool *page_pool_create(const struct page_pool_params *params); |
150 | ||
e54cfd7e | 151 | #ifdef CONFIG_PAGE_POOL |
c3f812ce JL |
152 | void page_pool_destroy(struct page_pool *pool); |
153 | void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *)); | |
458de8a9 | 154 | void page_pool_release_page(struct page_pool *pool, struct page *page); |
78862447 LB |
155 | void page_pool_put_page_bulk(struct page_pool *pool, void **data, |
156 | int count); | |
c3f812ce | 157 | #else |
1da4bbef IK |
158 | static inline void page_pool_destroy(struct page_pool *pool) |
159 | { | |
c3f812ce | 160 | } |
1da4bbef | 161 | |
c3f812ce JL |
162 | static inline void page_pool_use_xdp_mem(struct page_pool *pool, |
163 | void (*disconnect)(void *)) | |
164 | { | |
1da4bbef | 165 | } |
458de8a9 IA |
166 | static inline void page_pool_release_page(struct page_pool *pool, |
167 | struct page *page) | |
168 | { | |
169 | } | |
78862447 LB |
170 | |
171 | static inline void page_pool_put_page_bulk(struct page_pool *pool, void **data, | |
172 | int count) | |
173 | { | |
174 | } | |
c3f812ce | 175 | #endif |
1da4bbef | 176 | |
458de8a9 IA |
177 | void page_pool_put_page(struct page_pool *pool, struct page *page, |
178 | unsigned int dma_sync_size, bool allow_direct); | |
ff7d6b27 | 179 | |
458de8a9 IA |
180 | /* Same as above but will try to sync the entire area pool->max_len */ |
181 | static inline void page_pool_put_full_page(struct page_pool *pool, | |
182 | struct page *page, bool allow_direct) | |
ff7d6b27 | 183 | { |
57d0a1c1 JDB |
184 | /* When page_pool isn't compiled-in, net/core/xdp.c doesn't |
185 | * allow registering MEM_TYPE_PAGE_POOL, but shield linker. | |
186 | */ | |
187 | #ifdef CONFIG_PAGE_POOL | |
458de8a9 | 188 | page_pool_put_page(pool, page, -1, allow_direct); |
57d0a1c1 | 189 | #endif |
ff7d6b27 | 190 | } |
458de8a9 IA |
191 | |
192 | /* Same as above but the caller must guarantee safe context. e.g NAPI */ | |
ff7d6b27 JDB |
193 | static inline void page_pool_recycle_direct(struct page_pool *pool, |
194 | struct page *page) | |
195 | { | |
458de8a9 | 196 | page_pool_put_full_page(pool, page, true); |
6bf071bf JDB |
197 | } |
198 | ||
0afdeeed IA |
199 | static inline dma_addr_t page_pool_get_dma_addr(struct page *page) |
200 | { | |
201 | return page->dma_addr; | |
202 | } | |
203 | ||
57d0a1c1 JDB |
204 | static inline bool is_page_pool_compiled_in(void) |
205 | { | |
206 | #ifdef CONFIG_PAGE_POOL | |
207 | return true; | |
208 | #else | |
209 | return false; | |
210 | #endif | |
211 | } | |
212 | ||
1da4bbef IK |
213 | static inline bool page_pool_put(struct page_pool *pool) |
214 | { | |
215 | return refcount_dec_and_test(&pool->user_cnt); | |
216 | } | |
217 | ||
bc836748 SM |
218 | /* Caller must provide appropriate safe context, e.g. NAPI. */ |
219 | void page_pool_update_nid(struct page_pool *pool, int new_nid); | |
220 | static inline void page_pool_nid_changed(struct page_pool *pool, int new_nid) | |
221 | { | |
222 | if (unlikely(pool->p.nid != new_nid)) | |
223 | page_pool_update_nid(pool, new_nid); | |
224 | } | |
78862447 LB |
225 | |
226 | static inline void page_pool_ring_lock(struct page_pool *pool) | |
227 | __acquires(&pool->ring.producer_lock) | |
228 | { | |
229 | if (in_serving_softirq()) | |
230 | spin_lock(&pool->ring.producer_lock); | |
231 | else | |
232 | spin_lock_bh(&pool->ring.producer_lock); | |
233 | } | |
234 | ||
235 | static inline void page_pool_ring_unlock(struct page_pool *pool) | |
236 | __releases(&pool->ring.producer_lock) | |
237 | { | |
238 | if (in_serving_softirq()) | |
239 | spin_unlock(&pool->ring.producer_lock); | |
240 | else | |
241 | spin_unlock_bh(&pool->ring.producer_lock); | |
242 | } | |
243 | ||
ff7d6b27 | 244 | #endif /* _NET_PAGE_POOL_H */ |